Tangential fit of patient-specific guides

ABSTRACT

A bone preparation guide including a first patient-specific portion based on image data of a specific patient&#39;s bone and configured to match the patient&#39;s specific bone surface. A second patient-specific portion is based on image data of the specific patient&#39;s bone and configured to match the patient&#39;s specific bone surface. A patient-generic portion is configured to be a bone-facing portion supported by the first and the second patient-specific bone contacting members at a portion of the patient&#39;s bone surface not imaged during preparation of a preoperative plan.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 15/784,644, filed on Oct. 16, 2017, now issued as U.S. Pat. No. 10,426,491, which is a continuation of U.S. patent application Ser. No. 14/202,861, filed on Mar. 10, 2014, now issued as U.S. Pat. No. 9,826,981, which claims the benefit of U.S. Provisional Application Ser. No. 61/779,829, filed on Mar. 13, 2013. The entire disclosures of the above applications are incorporated herein by reference.

FIELD

The present disclosure relates to tangential fit patient-specific bone preparation guides.

BACKGROUND

This section provides background information related to the present disclosure, which is not necessarily prior art.

Patient-specific bone preparation guides often use MRI and CT data to create a three-dimensional model of a patient's bone. From the model, a pre-operative plan can be made and modified by a surgeon. The pre-operative plan includes a series of points, axes, and planes defined by specific-patient geometry. After the surgeon approves the pre-operative plan, a patient-specific bone preparation guide is made based on the plan to fit the patients bone. Obtaining three-dimensional MRI and CT data can be complicated and costly, particularly as compared to obtaining two-dimensional x-ray data. It would thus be advantageous to create a bone preparation guide from two-dimensional x-ray data that can be customized to fit a specific patient.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present teachings provide for a bone preparation guide including a first patient-specific portion based on image data of a specific patient's bone and configured to match the patient's specific bone surface. A second patient-specific portion is based on image data of the specific patient's bone and configured to match the patient's specific bone surface. A patient-generic portion is configured to be a bone-facing portion supported by the first and the second patient-specific bone contacting members at a portion of the patient's bone surface not imaged during preparation of a preoperative plan.

The present teachings further provide for a bone preparation guide including a plurality of first patient-specific bone contacting members customized based on two-dimensional image data of a specific patient to match the patient's specific bone geometry and provide a first bone coupling surface. A plurality of second patient-specific bone contacting members are customized based on two-dimensional image data of the specific patient to match the patient's specific bone geometry and provide a second bone coupling surface. A patient-generic portion is configured as a bone-facing surface to be supported by the first and the second patient-specific bone contacting members at a portion of the patient's bone surface not imaged during preparation of a preoperative plan.

The present teachings further provide for a method of customizing a bone preparation guide to correspond to specific bone geometry of a specific patient. The method includes analyzing two-dimensional image data of the specific patient's own bone geometry; developing a pre-operative plan based on the patient's own two-dimensional image data, first and second patient-specific bone contacting members of the guide are configured pursuant to the pre-operative plan to match the patient specific bone surface and couple the guide to the patient's own bone geometry, the first and the second patient-specific bone contacting members are further configured to support a patient-generic portion of the bone preparation guide over the bone such that the patient-generic portion faces a portion of the patient's bone surface not imaged during preparation of the pre-operative plan; coupling the guide to the patient's bone with the first and the second patient-specific bone contacting members; and guiding at least one of a first cutting instrument or a first guide member to the patient's bone using the guide.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure,

FIG. 1 is a perspective view of a bone preparation guide according to the present teachings;

FIG. 2 is a top view of the bone preparation guide of FIG. 1;

FIG. 3 is a bottom perspective view of the bone preparation guide of FIG. 1;

FIG. 4 is a side view of the bone preparation guide of FIG. 1;

FIG. 5A is a cross-sectional view of the bone preparation guide of FIG. 1;

FIG. 5B is another cross-sectional view of the bone preparation guide of FIG. 1

FIG. 6 is another perspective view of the bone preparation guide of FIG. 1;

FIG. 7 is another cross-sectional view of the bone preparation guide of FIG. 1;

FIG. 8 illustrates the bone preparation guide of FIG. 1 mounted to a tibia bone;

FIG. 9 is a side view of the one preparation guide of FIG. 1 mounted to the tibia bone;

FIG. 10 is a top view of the bone preparation guide of FIG. 1 mounted to the tibia bone;

FIG. 11 is a perspective view of another bone preparation guide in accordance with the present teachings;

FIG. 12 is another perspective view of the bone preparation guide of FIG. 11;

FIG. 13 illustrates the bone preparation guide of FIG. 11 mounted to a femur;

FIG. 14 is another view of the bone preparation guide of FIG. 11 mounted to a femur.

FIG. 15 is another bone preparation guide according to the present teachings;

FIG. 16 is a perspective view of the bone preparation guide of FIG. 15;

FIG. 17 illustrates the bone preparation guide of FIG. 15 mounted to a femur;

FIG. 18 is a perspective view of another bone preparation guide according to the present teachings;

FIG. 19 is a perspective view of the bone preparation guide of FIG. 18;

FIG. 20 is a side view of the bone preparation guide of FIG. 18; and

FIGS. 21 and 22 illustrate the bone preparation guide of FIG. 18 mounted at an acetabulum.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

The present teachings generally provide various bone preparation guides including patient-specific portions thereof. The guides can be used in for orthopedic surgery, such as, for example, joint replacement or revision surgery. The guides can be used either with conventional or patient-specific implant components and can be prepared with computer-assisted image methods. The patient-specific portions of the alignment guides are generally configured to match the anatomy of a specific patient, and are based on two-dimensional image data of the specific patient, such as x-ray data. The x-ray data can include any suitable number of x-ray images or scans, such as only two or more. The x-rays can be taken along first and second intersecting planes, or at any other suitable orientation or position. The patient-specific portions can be based directly on the image data (such as x-ray image data) or based on a three-dimensional model, which is based on the two-dimensional image data. The guides can also include patient-generic portions, which are not based on patient image data, or are based patient image data having fewer than the image data used for the patient-specific portions.

The patient-generic portions can be at least partially modeled based on historical data collected from preparation of previous patient-specific guides. For example, bone dimensions collected from patients of a similar sex, height, weight, age, and race can be used to estimate bone dimensions of a new patient of a similar body type and background. The patient-generic portions can be modeled to best-fit the patient based on the available data. A three-dimensional bone model can be made based on the historical data, and the patient-generic portions can then be made based on the three-dimensional model. Alternatively, the patient-generic portions can be made based directly on the historical data.

The patient-specific portions of the alignment guides are designed and prepared preoperatively using anatomic landmarks, such as osteophytes, for example, and can be mounted intra-operatively without any registration or other guidance based on their unique patient-specific surface guided by the patient's anatomic landmarks.

The guides can include custom-made guiding formations, such as, for example, guiding bores or cannulated guiding posts or cannulated guiding extensions or receptacles that can be used for supporting or guiding other non-custom instruments, such as guides, reamers, cutters, cutting guides and cutting blocks or for inserting pins or other fasteners according to a surgeon-approved pre-operative plan for performing various resections as indicated for an arthroplasty, joint replacement, resurfacing or other procedure for the specific patient.

The guides can also include resection or cutting formations, such as cutting slots or cutting edges or planes used for guiding a cutting blade to perform bone resections directly through the guides. The guides can be used in minimally invasive surgery. Various alignment/resection guides and preoperative planning procedures are disclosed in commonly assigned U.S. patent application Ser. No. 11/756,057, filed on May 31, 2007; U.S. patent application Ser. No. 12/211,407, filed Sep. 16, 2008; U.S. patent application Ser. No. 11/971,390, filed on Jan. 9, 2008, U.S. patent application Ser. No. 11/363,548, filed on Feb. 27, 2006; and U.S. patent application Ser. No. 12/025,414, filed Feb. 4, 2008. The disclosures of the above applications are incorporated herein by reference.

As disclosed, for example, in the above-referenced U.S. patent application Ser. No. 11/756,057, filed on May 31, 2007, in the preoperative planning stage for a joint replacement or revision procedure, a series of x-rays of the relevant anatomy of the patient can be performed at a medical facility or doctor's office. The scan data obtained can be sent to a manufacturer. The scan data can be used to construct a three-dimensional image of the joint and provide an initial implant fitting and alignment in a computer file form or other computer representation. The initial implant fitting and alignment can be obtained using an alignment method, such as alignment protocols used by individual surgeons.

The outcome of the initial fitting is an initial surgical plan that can be printed or provided in electronic form with corresponding viewing software. The initial surgical plan can be surgeon-specific, when using surgeon-specific alignment protocols. The initial surgical plan, in a computer/digital file form associated with interactive software, can be sent to the surgeon, or other medical practitioner, for review. The surgeon can incrementally manipulate the position of images of various implant components in an interactive image of the joint. Additionally, the surgeon can select or modify resection planes, types of implants and orientations of implant insertion. After the surgeon modifies and/or approves the surgical plan, the surgeon can send the final, approved plan to the manufacturer.

After the surgical plan is approved by the surgeon, bone preparation guides including patient-specific areas can be designed by configuring and using a CAD program or other imaging software, such as the software provided by Materialise, for example, according to the surgical plan. Computer instructions of tool paths for machining the patient-specific alignment guides can be generated and stored in a tool path data file.

The tool path can be provided as input to a CNC mill or other automated machining system, and the alignment guides can be machined from polymer, ceramic, metal or other suitable material. The guides can also be manufactured by various other methods, stereolithography, laser deposition, printing, and rapid prototyping methods. The alignment guides are sterilized and shipped to the surgeon or medical facility, for use during the surgical procedure. Various patient-specific knee alignment guides and associated methods are disclosed in the commonly assigned U.S. application Ser. No. 11/756,057, filed on May 31, 2007 (published as 2007/0288030 on Dec. 13, 2007), which is incorporated herein by reference.

A patient-specific alignment guide can be used to drill holes through corresponding bone of the joint surface and to guide alignment pins through the holes. The alignment guide is then removed leaving the alignment pins for supporting and cutting instruments to make various resections in the bone in preparation for receiving a joint implant.

With initial reference to FIGS. 1-4, a bone preparation guide according to the present teachings is generally illustrated at reference numeral 10. Although the bone preparation guide 10 is illustrated as being a tibia guide, the present teachings can be applied to most any bone guide, such as the femoral guides 110 and 210, and the acetabular cup bone preparation guide 310 described herein.

The bone preparation guide 10 generally includes a main body 12. The main body 12 includes an outer surface 14 and an inner surface 16, which is generally a bone facing surface. The main body 12 further includes an inferior end 18 and a superior end 20, which is opposite to the inferior end 18.

The main body 12 of the bone preparation guide 10 defines a first guide aperture 22 and a second guide aperture 24. Each of the first and second guide apertures 22 and 24 generally extend between the outer surface 14 and the inner surface 16. The guide apertures 22 and 24 can be arranged at any suitable location about the main body 12, and at any suitable angle, to direct guide pins, K-wire, or any other suitable guide device to a patient's bone surface. The guide pins, K-wire, or other guide device can be used for any suitable surgical purpose, such as for supporting a cutting guide at a proper position at a bone to be prepared.

The bone preparation guide 10 further includes a first patient-specific bone contacting portion 26 and a second patient-specific bone contacting portion 28. The first patient-specific bone contacting portion 26 is proximate to the inferior end 18, and the second patient-specific bone contacting portion 28 is proximate to the superior end 20.

Extending from the second patient-specific bone contacting portion 28 at the superior end 20 are first and second guide members 30 a and 30 b. The guide members 30 a and 30 b can be elongated rods for locating the bone preparation guide 10 on a tibia bone. The guide members 30 a and 30 b can be patient-specific according to the pre-operative plan and can be included as part of the second patient-specific bone contacting portion 28. The guide members 30 a and 30 b can be configured to abut and at least partially extend across a patient's superior tibial condyles.

A first group of patient-specific bone contacting members 32 a-32 e are included at the first patient-specific bone contacting portion 26. Each one of the patient-specific bone contacting members 32 a-32 e include a base 34, an elongated portion 36 extending from the base 34, and a tip 38 at an end of the elongated portion 36. The elongated portion 36 can extend from the base 34 at any suitable distance and angle to allow the tips 38 based on the pre-operative plan to couple with a specific bone surface of a specific patient. For example, the first group of patient-specific bone contacting members 32 a-32 e can be configured to couple with a particular patient's inferior tibial condyle. The tips 38 can be pointed as illustrated, can be blunt, or can be provided with any suitable shape or configuration to facilitate coupling of the first patient-specific bone contacting portion 26 with bone and/or cartilage.

A second group of patient-specific bone contacting members 40 a-40 d are provided at the second patient-specific bone contacting portion 28. The bone contacting members 40 a-40 d extend from the inner surface 16 of the main body 12. The bone contacting members 40 a-40 d each include a base 42 at the inner surface 16, an elongated portion 44 extending from the base 42, and a tip 46 at a distal end of the elongated portion 44. The patient-specific bone contacting members 40 a-40 d can be arranged in any suitable manner in order to couple with a particular surface of a specific patient's bone. For example, the bone contacting member 40 a-40 d can be arranged, sized, and shaped to couple with a specific patient's superior tibial condyle.

The bone preparation guide 10 further includes an intermediate or patient-generic portion 50 between the first patient-specific bone contacting portion 26 and the second bone contacting portion 28. The patient-generic portion 50 is not patient-specific like the first and second patient-specific bone contacting portions 26 and 28, but is rather generic to a plurality of different patients. The patient-generic portion 50 is thus not shaped to conform to specific dimensions and surface features of a patient's bone. The patient-generic portion 50 is typically arranged to be suspended over or contact a patient's bone by each of the first and second patient-specific portions 26 and 28. The patient-generic portion 50 thus includes a portion of the bone facing surface or inner surface 116 described herein.

The bone preparation guide 10 can be made of any suitable material, or combination of different suitable materials. For example, the guide 10 can be made entirely of a suitable biocompatible metallic material such as high molecular weight polyethylene. With reference to FIG. 5A, the bone preparation guide 10 can include a suitable compliant material at the patient-generic portion 50, such as any suitable polymeric or rubber. With reference to FIG. 5B, the bone preparation guide 10 can be made entirely of a compliant material, such as rubber.

With additional reference to FIG. 6, the patient-generic portion 50 can include pins 60. The pins 60 are movable so as to extend from the inner surface 16 of the patient-generic portion 50 at varying distances in order to accommodate various surface features of a patient's bone, without being specifically designed to fit any specific patient. Although three pins 60 are illustrated, any suitable number of pins can be included.

With additional reference to FIG. 7, the patient-generic portion 50 can include a compliant layer 70 mounted at, or integrated into, the inner surface 16 of the bone preparation guide 10. The compliant layer 70 can be any suitable layer configured to the form to, or in any way accommodate, surface features of a patient's bone. For example, the compliant surface 70 can be any suitable flexible material such as rubber. The compliant layer 70 can be provided at any location on, in, or about the bone preparation guide 10 to correspond to and accommodate an area of the patient's bone that has not been imaged

With additional reference to FIGS. 8-10, the bone preparation guide 10 is illustrated as coupled to tibia 80 of a specific patient. The tibia 80 includes a lateral condyle 82 and a medial condyle 84. The bone preparation guide 10 is coupled to the tibia 80 by arranging the first group of patient-specific bone contacting members 32 a-32 e at an inferior-anterior surface on each of the medial and lateral condyles 82 and 84. The bone preparation guide 10 is thus patient-specific at the patient-specific bone contacting members 32 a-32 e generally along a first plane A (see FIG. 3) that an x-ray of the patient is taken. The patient-specific bone contacting members 32 a-32 e thus mate with, and match, the patient's bone.

The second group of patient-specific bone contacting members 40 a-40 d are arranged at a superior surface of the tibia 80 on and/or between the lateral condyle 82 and the medial condyle 84. The guide members 30 a and 30 b extend in the superior/posterior direction from the superior end 20 of the bone preparation guide 10 along the superior surface of the tibia 80 between and/or on the lateral and medial condyles 82 and 84. The bone preparation guide 10 is thus patient-specific at the patient-specific bone contacting members 40 a-40 d generally along a second plane B (see FIG. 3) that an x-ray of the patient is taken. The patient-specific bone contacting members 40 a-40 d thus mate with, and match, the patient's bone. The bone preparation guide 10 is generic at the patient-generic portion 50 between the first plane A and the second plane B. Because the patient-specific portions at the first and second planes A and B can accurately position the bone preparation guide 10 at the patient's bone based on two-dimensional x-ray data, use of an MRI or other costly and complex three-dimensional imaging is not necessary.

The first and second guide apertures 122 and 124 will thus be arranged at the tibia 80 at a specific location according to the pre-operative plan for the specific patient in order to permit placement of any suitable guide at a desired location pursuant to the pre-operative plane. Any suitable cutting device or drilling device, for example, can be coupled to the pins in order to prepare the tibia 80 to receive an implant. The bone preparation guide 10 itself can include a cutting guide surface, such as the cutting guide 332 described herein in connection with the description of the bone preparation guide 310.

With reference to FIGS. 11 and 12, an additional bone preparation guide according to the present teachings is illustrated at reference numeral 110. The bone preparation guide 110 can be used to prepare any suitable bone during surgery, such as a femur. The bone preparation guide 110 includes a main body 112 with an outer surface 114 and an inner surface 116, which can be a bone facing surface. The bone preparation guide 110 further includes an inferior end 118 and a superior end 120.

At the superior end 120 is a first patient-specific bone contacting portion 126 of the main body 112. At the first patient-specific bone contacting portion 126, the main body 112 includes a first group of patient-specific bone contacting members 132 a-132 d. Each of the bone contacting members 132 a-132 d includes a base portion 134, an elongated portion 136 extending from the base portion 134, and a tip 138 at a distal end of the elongated portion 136. The patient-specific bone contacting members 132 a-132 d can be configured and sized in any suitable manner to contact a specific portion of the patient's bone, such as the patient's anterior portion of the femur at the lateral condyle, as further described herein and illustrated at FIGS. 13 and 14. Like the patient-specific bone contacting members 32 a-32 e, the patient specific bone contacting members 132 a-132 d are patient-specific along a plane C that an x-ray is taken.

The second patient-specific bone contacting portion 128 includes a second group of patient-specific bone contacting members 140 a and 140 b at the inner surface 116 thereof. The bone contacting members 140 a and 140 b are similar to the bone contacting members 132 a-132 d, and can be configured to contact any suitable portion of the patient's bone, such as a lateral portion of the patient's lateral condyle. The patient specific bone contacting members 140 a and 140 b are patient-specific along a plane that an x-ray is taken.

The main body 112 defines a first guide aperture 122 proximate to the second patient-specific bone contacting portion 128, and a second guide aperture 124 proximate to or at a third patient-specific bone contacting portion 130. Each of the first and the second guide apertures 122 and 124 extend through the main body 112 between the outer surface 114 and the inner surface 116. The first and the second guide apertures 122 and 124 can be patient-specific and thus configured to direct any suitable guide, such as guide pins or K-wire, to a specific bone location of a specific patient's femur.

The third patient-specific bone contacting portion 130 includes a third group of patient-specific bone contacting members 142 a-142 c. The bone contacting member 142 a is similar to the bone contacting members 132 a-132 d, and thus includes a base 144 and a pointed tip 146 extending therefrom. The bone contacting member 142 a is generally between bone contacting members 142 b and 142 c, which are guide members or rods extending from inner surface 116 at the third patient-specific bone contacting portion 130. The guide members or rods 142 b and 142 c are generally arranged to be seated on opposite sides of a specific patient's lateral condyle at a distal end thereof. The patient specific bone contacting members 142 a-142 c are patient-specific along a plane C that an x-ray is taken.

The bone preparation guide 110 further includes an intermediate patient-generic portion 150, which is not patient-specific and is thus configured to sit on or over most any bone surface, and is thus patient-generic between at least the planes C and E. The patient-generic portion 150 extends between the first patient-specific bone contacting portion 126 and the third patient-specific bone contacting portion 130. The patient-generic portion 150 is spaced apart from the second patient-specific bone contacting portion 128 to define an aperture 152 therebetween. An additional patient-generic intermediate portion can be provided between the first patient-specific bone contacting portion 126 and the second patient-specific bone contacting portion 123 at reference numeral 154. Yet an additional patient-generic intermediate portion 156 can be provided between the second patient-specific bone contacting portion 128 and the third patient-specific bone contacting portion 130.

The bone preparation guide 110 can be made in a manner similar to that described above with respect to the bone preparation guide 10. For example, the bone preparation guide 110 can be made of any suitable metallic material, compliant material, or any combination thereof. With respect to the patient-generic portions 150, 154, and 156 in particular, they can be made of any suitable compliant material, such as rubber, include the pins 60 illustrated in FIG. 6, and can be rigid with the compliant portion 70 mounted thereto in order to accommodate bone features that were not specifically modeled or imaged for the patient as part of the pre-operative plan.

With additional reference to FIGS. 13 and 14, the bone preparation guide 110 is illustrated coupled to a femur 160. The bone preparation guide 110 is arranged such that the third patient-specific bone contacting portion 130 is at the distal end of lateral condyle 162. Specifically, the patient-specific guide members 142 b and 142 c are arranged on lateral and medial sides of the lateral condyle 162 respectively. The bone contacting member 142 a is also coupled to the lateral condyle 162 at a distal end thereof.

The first group of patient-specific bone contacting members 132 a-132 d are coupled to the femur 160 at generally an anterior surface thereof. The second group of patient-specific bone contacting members 140 a and 140 b are coupled to a lateral surface of the lateral condyle 162. The first and second guide apertures 122 and 124 are thus arranged at the lateral condyle 162 according to the pre-operative plan in order to direct guide pins to predetermined locations of the lateral condyle 162. The pins can be used to couple with any suitable standard guide.

With additional reference to FIGS. 15-17, an additional bone preparation guide is illustrated at reference numeral 210. The guide 210 generally includes a main body 212 with an outer surface 214 and an inner surface 216, which is generally a bone facing surface. The guide 210 includes an inferior end 218 and a superior end 220. The inferior end 218 is opposite to the superior end 220.

The main body 212 defines a first guide aperture 222 and a second guide aperture 224. The first guide aperture 222 is proximate to the superior end 220 and the second guide aperture 224 is proximate to the inferior end 218. The first and second guide apertures 222 and 224 extend through the main body 212 between the outer surface 214 and the inner surface 216.

The bone preparation guide 210 generally includes a first patient-specific portion 226, a second patient-specific portion 228, and a third patient-specific portion 230, which are patient-specific generally along x-ray planes F, G, and H respectively Between the first and second patient-specific portions 226 and 228 is a first patient-generic portion 232. Between the second and third patient-specific portions 228 and 230 is a second patient-generic portion 234. Between the third patient-specific portion 230 and the first patient-specific portion 226 is a third patient-generic portion 236. The patient-generic portions 232, 234, and 236 thus include a portion of the bone facing surface or inner surface 216.

A first group of patient-specific bone contacting members 240 a-240 c are provided at the first patient-specific portion 226. Each one of the patient-specific bone contacting members 240 a-240 c includes a base 242, an elongated portion 244, and a tip 246, which is at an end of the elongated portion 244. A second group of patient-specific bone contacting members 250 a and 250 b are located at the second patient-specific portion 228. The patient-specific bone contacting members 250 a and 250 b are similar to the bone contacting members 240 a-240 c and are configured to contact a lateral portion of the patient's lateral condyle, for example. The patient-specific bone contacting members 240 a-240 c are configured to contact, for example, the patient's femur at an anterior portion thereof. A third group of patient-specific bone contacting members 252 a and 252 b are at the third patient-specific portion 230, and extend from the inner surface 216. The bone contacting member 252 a and 252 b are similar to the bone contacting members 240 a-240 c. The bone contacting members 250 a and 250 b, and can be configured to contact a distal portion of a patient's lateral condyle.

The bone preparation guide 210 can be made of any suitable material. For example, the guide 210 can be made entirely of a rigid material, such as a rigid metallic. The bone preparation guide 210 can also include any suitable compliant materials, or can be entirely made of a compliant material, such as rubber. The patient-generic portions 232, 234, and 236 can include the pins 60 of FIG. 6 to accommodate nearly any bone feature of the patient not modeled as part of the preoperative plane.

An additional bone preparation guide according to the present teachings is illustrated in FIGS. 18-20 at reference numeral 310. The bone preparation guide 310 generally includes a main body 312 with an outer surface 314 and an inner surface 316. The main body 312 defines a first guide aperture 318 and a second guide aperture 320. The first and second guide apertures 318 and 320 extend between the outer surface 314 and the inner surface 216, and are positioned and angled to direct any suitable guide, such as pins or K-wire, to any suitable location at a specific patient's bone surface, such as at the patient's acetabular cup.

The bone preparation guide 310 further includes a cutting guide 322, which extends through the main body 312 between the outer surface 314 and the inner surface 316, which is a bone facing surface and includes the patient-generic portion 356. The cutting guide 322 defines a slot 324. The cutting guide 322 can be positioned at any suitable location about the bone preparation guide 310, such as between the first and second guide apertures 318 and 320. The cutting guide 322 can also be defined by any suitable outer edge of the guide 310. The cutting guide 322 can be positioned and angled in any suitable manner pursuant to the pre-operative plan in order to direct a suitable cutting instrument to the patient's bone in order to prepare the patient's bone pursuant to the pre-operative plan.

The bone preparation guide 310 further includes a first patient-specific portion 330 and a second patient-specific portion 322. The first patient-specific portion 330 is generally at a medial side of the guide 310, and the second patient-specific portion 332 is generally at a lateral side of the guide 310.

The first patient-specific portion 330 includes a first group of patient-specific bone contacting members 334 a-334 c. The first patient-specific bone contacting member 334 a generally includes a base 336 at the inner surface 316, an elongated portion 338 extending from the base 336, and a tip 340 at a distal end of the elongated portion. The first patient-specific bone contacting member 334 a can have any suitable length and orientation in order to contact a predetermined portion of the patient's acetabular cup pursuant to the pre-operative plan. The bone contacting members 334 b and 334 c are generally guide members or rods extending from the inner surface 316 at any suitable location, distance, and angle pursuant to the pre-operative plan in order to mount the bone preparation guide 310 to bone.

The second patient-specific portion 332 includes a second group of patient-specific bone contacting members 342 a-342 c. Each one of the patient-specific bone contacting members 342 a, 342 b, and 342 c are similar to the patient-specific bone contacting members 334 a, 334 b, and 334 c respectively. The patient-specific bone contacting members 342 a-342 c can be arranged and configured in any suitable manner pursuant to the pre-operative plan independent of the bone patient-specific bone contacting members 334 a-334 c.

Extending from an outer edge 350 of the main body 312 is a third group of patient-specific bone contacting members 352 a-352 c. The bone contacting members 352 a-352 c are generally similar to the patient-specific bone contacting members 334 a and 342 a. The patient-specific bone contacting members 352 a-352 c can be arranged at any suitable location about the outer edge 350 pursuant to the pre-operative plan, and can have any suitable length, angle, or any suitable arrangement generally.

At approximately a radial center of the inner surface 316 is a center patient-specific bone contacting member 354. The center patient-specific bone contacting member 354 can extend from the inner surface 316 at any suitable location, and to any suitable length, pursuant to the pre-operative plan in order to contact a specific portion of the patient's bone, such as a patient's acetabulum 404, as called for by the pre-operative plan.

Surrounding the center patient-specific bone contacting member 354 is a patient-generic portion 356. The patient-generic portion 356 can be made of any suitable material to accommodate generic bone features. For example, the patient-generic portion 356 can be made of any suitable compliant material, such as rubber. To accommodate bone features not addressed or imaged in the pre-operative plan, the patient-generic portion can include the pins 60 illustrated in FIG. 6. The patient-generic portion 356 can also be rigid and include the compliant portion 70 mounted thereto.

With reference to FIGS. 21 and 22, a pelvic bone is illustrated at reference numeral 402. The pelvic bone 402 includes an acetabulum 404. The bone preparation guide 310 is configured to be coupled to the pelvic bone 402 at the acetabulum 404. The bone preparation guide 310 is arranged such that the first patient-specific portion 330 is generally at a medial area of the acetabulum 404, and the second patient-specific portion 332 is at a lateral portion. The center patient-specific bone contacting member 354 is proximate to the acetabular fossa of the acetabulum 404. The outer patient-specific bone contacting member 352 a-352 c are generally at the acetabular margin.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A method of customizing a bone preparation guide to correspond to specific bone geometry of a specific patient comprising: analyzing two-dimensional image data of the specific patient's own bone geometry; developing a pre-operative plan based on the patient's own two-dimensional image data, first and second patient-specific bone contacting members of the guide are configured pursuant to the pre-operative plan to match the patient's specific bone surface and couple the guide to the patient's own bone geometry, the first and the second patient-specific bone contacting members comprising elongate bodies extending along central axes away from a portion of the bone preparation guide from which they are connected configured to support a patient-generic portion of the bone preparation guide over the bone such that the patient-generic portion faces a portion of the patient's bone surface not imaged during preparation of the preoperative plan; coupling the guide to the patient's bone with the first and the second patient-specific bone contacting members; and guiding at least one of a first cutting instrument or a first guide member to the patient's bone using the guide.
 2. The method of claim 1, further comprising obtaining the two-dimensional image data from a first x-ray taken along a first plane and a second x-ray taken along a second plane that is orthogonal to the first plane and the first and second patient-specific bone contacting members are configured based only on data obtained from the first and second x-rays.
 3. The method of claim 2, wherein the first patient-specific bone contacting member comprises one of a plurality of patient-specific bone contacting members each having a tip arranged within the first plane.
 4. The method of claim 1, wherein developing the preoperative plan includes creating a three-dimensional bone model based on the two-dimensional image data.
 5. The method of claim 4, wherein developing the preoperative plan includes configuring the first and second patient-specific bone contacting members based on the three-dimensional bone model.
 6. The method of claim 1, wherein developing the preoperative plan includes configuring the first and second patient-specific bone contacting members based on historical data from other patients, the historical data including age and physical dimensions.
 7. The method of claim 1, wherein developing the preoperative plan includes configuring a plurality of third patient-specific bone contacting members positioned at different angles relative to the first and second patient-specific bone contacting members.
 8. The method of claim 1, wherein the method further comprises performing a bone resection using the first cutting instrument.
 9. The method of claim 1, wherein the bone preparation guide comprises: a main body defined by the portions from which the elongate bodies extend; and the first and second patient-specific bone contacting members, each of which comprises: a base extending from the main body to which an elongate body is connected; and a blunted tip connected to the elongate body.
 10. The method of claim 1 wherein the elongate bodies of the first and second patient-specific bone contacting members comprise tips oriented perpendicular to the patient's specific bone surface.
 11. A method of designing a patient-specific bone preparation guide for use in joint replacement surgery: obtaining at least two x-ray scans on one or more of a patient's bones to obtain two-dimensional image data of the patient's specific bone geometry, the first x-ray scan taken in a first plane and the second x-ray scan taken in a second plane orthogonal to the first plane; and customizing the patient-specific bone preparation guide for the patient using the two-dimensional image data to configure a first and a second plurality of patient-specific bone contacting members to correspond to the specific bone geometry of the patient, the first and second plurality of patient-specific bone contacting members supporting a patient-generic portion of the bone preparation guide over the patient's bone, the first and second plurality of patient-specific bone contacting members further configured to couple the patient-specific bone preparation guide to the patient's bone; wherein the first plurality of patient-specific bone contacting members are located along the first plane; and wherein the second plurality of patient-specific bone contacting members are located along the second plane.
 12. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes configuring the first and second plurality of patient-specific bone contacting members based on a three-dimensional bone model created from the two-dimensional image data.
 13. The method of claim 11, wherein the first and second plurality of patient-specific bone contacting members are configured by sizing, shaping, or arranging the first and second plurality of patient-specific bone contacting members to correspond to the specific bone geometry of the patient.
 14. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes configuring the first and second plurality of patient-specific bone contacting members to include pointed tips configured to engage with the patient's bone at specific locations.
 15. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes configuring patient-specific guide rods coupled to the patient-specific bone preparation guide, the patient-specific guide rods configured to contact a surface of the patient's bone and aid in positioning the patient-specific bone preparation guide on the patient's bone.
 16. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes selecting one of a variety of different generic portions, the one of the variety of generic portions based on historical data from other patients, the historical data including age and physical dimensions.
 17. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes forming at least one guide aperture in the patient-specific bone preparation guide configured to direct a guide member to the patient's bone, such as a guide pin.
 18. The method of claim 11, wherein the patient-specific bone preparation guide comprises a tibia guide, a femoral guide, or an acetabular guide.
 19. The method of claim 11, wherein customizing the patient-specific bone preparation guide includes configuring the patient-specific bone preparation guide to comprise: a main body formed of a plastic; and the first and second patient-specific bone contacting members, each comprising: a base extending from the main body; an elongate portion connected to the base; and a tip connected to the elongate portion, the tip formed of metal.
 20. The method of claim 19, wherein the elongate portions extend perpendicular from the main body and the tips extend perpendicular to surfaces of the patient's bone.
 21. The method of claim 11, wherein customizing the patient-specific bone preparation guide for the patient using the two-dimensional image data to configure a first and a second plurality of patient-specific bone contacting members to correspond to the specific bone geometry of the patient further comprises using only the first and second x-ray scans to customize the patient-specific bone preparation guide along the first and second planes and configuring the patient-specific generic portion to be between the first and second planes such that a full three-dimensional model of the patient's bones are not needed. 